Yokomo YOKR12-37SH X Shock Hard Spring for R/C Suspension Tuning  [YOKR12-37SH]

Firm-rate shock springs for precise setup

This is an RC-scale shock spring intended for use in general R/C spring sets and suspension tuning. The Yokomo YOKR12-37SH X Shock Hard Spring provides a harder spring rate compared with standard soft or medium coils, and is intended to change suspension response rather than serve as a structural component.

Installation is straightforward for anyone familiar with threaded shocks: remove the damper shaft assembly, swap the coil onto the shock body, restore preload and retainers, then verify free travel and damping action. No special tools are required beyond standard shock disassembly tools and a clean workspace.

On-track tuning role: a hard-rate shock spring increases ride stiffness, reduces body roll and squat under acceleration, and shifts the balance toward firmer compression resistance. Expect changes to both compression and rebound feel at the wheel, so pair the spring with an appropriate shock oil and piston setup to achieve the desired damping balance.

Practical tips: change only one parameter at a time when tuning, test on consistent surface conditions, and record damper settings so you can return to a known baseline. If the chassis feels unsettled over small bumps after fitting a harder spring, reduce preload or soften shock oil rather than reverting immediately to a softer spring.